Chronograph



A. L. LOOMIS.

CHRONOGRAPH.

APPLICATION FILED AUG 15. 1919.

1,409,30 ate fed Mar. 14, 1922.

ALFRED L. LOOMIS, OF TUXEDO PARK, NEW YORK.

CHRONOGRAPH.

Specification of Letters Patent.

Patented Mar. 14, 1922.

Application filed August 16, 1919. Serial No. 317,986.

(FILED UNDER THE ACT OF MARCH 3, 1883, 22 STAT. L, 625.)

T aZZ whom it may concern:

Be it known that I, ALFRED L. LooMIs, a citizenv of the United States, and a resident of Tuxedo Park, Orange County, and State of New York, have invented an Improvement in Qhronographs, of which the followingris a specification.

he invention described herein may be used .by the Government or any ofits oflicers or employees in rosecution of work for the Government, or y any other person in the United States, without payment of any royalty thereon.

This invention relates to chronographs or other recording instruments used to graphically record the occurrence of events whether 'takin lace at fixed or variable intervals, and ea s more specifically with the carrier of, or support for the recording medium.

To that end, an object ofthe invention is to improve the rotating drum usually employed in most recording instruments, by the rovision of means of construction, which shall increase the accuracy, convenience and speed of operating such instruments.

The invention is particularly applicable to instruments in which the record surface moves at a high rate of speed in order that 80 short time intervals, for instance, may be indicated on the surface and measurable with great accuracy Such conditions exist in instruments used to graphically record the exceedin small time intervals measured in 85 determining the velocity of projectiles and shell fragments, or the rate of propagation of a detonation wave.

Another object is to so construct the car rier for the record medium, that the latter 40 may be applied to and removed from the rotating support without interfering with its rotation and without necessitating the dismounting or removal of any part of the a paratus.

46 A further object of the invention 'is the construction of a record support in which centrifugal force is. used to maintain the record medium or strip in place, thus dispensing with any fastening means, which might tend to unbalance the carrier or vary the true length of the record surface.

A preferred embodiment of the invention the record stri is disclosed in the accompanying drawings. 1n which- Fig. 1 is a view showing the drum and record strlp in cross section, and a means for rotating the drum, and

Fig. 2 is a perspective view of the carrier or drum.

The record carrier is shown in the form of a shallow, cup-shaped cylinderor drum 1 of cast aluminum or other material mounted with its axis vertical. The central spindle of the drum is connected to and driven at a high rate of speed by any suitable means, in the illustration, a small electric motor 2, supported on a bracket arm carrying a pivot rod 82 on which is mounted an insulation block 81 in which block the spark points 43, 43 and 43" are secured. The inner periphery of the drum carries the record surface3, shown as a narrow strip,'or ribbon, of prepared paper or other suitable substance held there solely by the centrifugal force developed by the rotation of the carrier.

The spark points and the drum 1 arein electrical connection with respective screens, not shown, so that, as a projectile passes through each screen circuit is made to cause a spark to pass between the point and the drum, piercin the ribbon or strip 3. Knowing the speedo the drum and having the distances between the spark punctures of the ribbon, the speed of the projectile can be determlned.

Below the drum is conventionally shown a common form of governor 5 mounted on the shaft 4 to maintain the motor constant,'and as this invention is not concerned with it no further description thereof is necessar The drum is balanced and acts as a flywheel for the motor and by the use" of centrifugal force all gluing or pasting of or surface is eliminated. The errors liab e to such procedure, as the ulling away of the strip from the carrier, if secured to the outside of the drum, due to its rotation, or the irregularities of the surface, due to the varying thickness of the adhesive layer employed, are also thus eliminated. The balance of the drum is also maintained, as could not be the result were the rate of speed of Y it necessary to employ clips or the like to maintain t e strip on the carrier.

The rate of speed of the drum, being constant and determined, and the circumference or rather inner periphery being accurately known, the time interval between the occurrence of any two events is of simple determination. Marks being obtained on the record strip in any well known manner, as by any means of styluses or electrical sparks, the linear measurement of the distance between such. marks is all that is necessary. 7'

The record strip, after marks have been made, may be removed Without stopping the rotation of the carrier as but a very slight force of the fingers is required to lift the strip out. The new strip may similarly be fed into the drum Without tion. The strip need not be exactly of the same length as the inner periphery of the drum.

What is claimed as new and desired to secure by Letters Patent is: In a chronograph, a source of shaft rotated by said power, a shal ow cupshaped drum mounted on the shaft and acting as a fly wheel therefor, the inner periphery of the drum providing a surface against which a stra of thin record material is held, when the s aft is rotated, by the act-ion of centrifugal force alone.

ALFRED L. LooMIs.

ower, a

stopping its rota-* 

